I could not understand the implication in this sentence, especially the "piecrust collars and smell of horse". I am totally lost! Could anyone help please?

The context is :

Will (a quadriplegic in wheelchair) and I (his carer) are going to the wedding of Will's ex-girlfriend, who is going to marry Will's former best friend. It's obvious I don't want him to go to the wedding, because I was worried for him. Nathan is Will's medical carer.

The sentence is :

……and there was Will, in a dark suit and a cornflower-blue shirt with
a tie. He was clean-shaven, and carried a faint tan on his face. The
shirt made his eyes look peculiarly vivid. They seemed, suddenly, to
carry a glint of the sun.

1 Answer
1

In the 1980s and later, blouses or dresses with a 'pie crust' collar were popular among young women of the British upper class. There is a stereotype that such women spend a lot of time riding horses. The carer is speaking disparagingly of the social background of the bridesmaids.